Automotive transverse-mounted power units

ABSTRACT

A power unit mounted across the longitudinal axis of a motor vehicle comprises a torque converter casing, a main transmission mechanism and differential gear casing connected to the power unit along orthogonal assembling planes and centered to one another by means of a cylindrical fitting. A detachable casing section assembled on the one hand to the main casing of the transmission mechanism along an assembling plane perpendicular to the assembling plane of the power unit crankcase and on the other hand to the torque converter casing is provided.

United States Patent Piret 1 Nov. 21, 1972 [54] AUTOMOTIVE TRANSVERSE-2,913,927 11/1959 Issigonis ..74/701 MOUNTED POWER UNITS 3,017,787 1/1962 Payne ..74/701 [72] Inventor: Jean Piret, Billancourt, France 2 g z00 on [73] Assignees: Regie National des Usines Renault,

Bufmcwrt; Automoblles Peugeot Primary Examiner-Arthur T. McKeon Pansboth of fig-n99 Att0rneyStevens, Davis, Miller & Mosher [22] Filed: vJan. 22, 1971 21] Appl. No.: 108,729 [57] ABSTRACT A power unit mountedacross the longitudinal axis of a motor vehicle comprises a torqueconverter casing, a [30] Forelgn Application Pnomy Data maintransmission mechanism and differential gear Jan. 26, 1970 France..7002586 i g nn ted to the power unit along orthogonal assemblingplanes and centered to one another by U-S. Clmean of a ylindrical Adetachable casing sec- [51] Int. Cl. ..Fl6h 37/08, F16h 57/02 tionassembled on the one hand to the main casing f [58] Fleld of Search..74/695, 701 the transmission mechanism along an assembling planeperpendicular to the assembling plane of the [56] References cued powerunit crankcase and on the other hand to the UNITED STATES PATENTS torqueconverter casing is provided.

2,751,798 6/1956 Keese et a] ..74/701 X 8 Claims, 3 Drawing Figures 27 4o O o o 0 o o O a 24 o o T o o -7 2 J: I '6 o L 0 0 4 o l 14;

L 1 2a -9 823 I 4 43 12 PATENTED Nov 2 1 1972 SHEET 2 OF 3 SHEET 3 [IF 3AUTOMOTIVE TRANSvERSE-MOUNTED POWER UNITS The present invention relatesin general to the arrangement of power and transmission units disposedtransversely in relation to the longitudinal median axis of a motorvehicle and has specific reference to an arrangement of a power andtransmission mechanism of the type in which a given ratio between therotational velocity of an internal combustion engine and the road wheelsof an automotive vehicle can be obtained automatically, this mechanismbeing designated hereinafter under the general term of automaticchange-speed transmission.

As a rule, in known mechanisms of this character the following mainelements are found the hydrokinetic torque converter providing thecoupling between the output end of the engine crankshaft and the inputshaft of the change-speed transmission the input shaft of thechange-speed transmission the output shaft of the change-speedtransmission the epicyclic gear train mechanism providing a series ofratios between the velocities of the input and output shafts of thetransmission mechanism, respectively the hydraulic-controlled system ofcoupling members providing the engagement of, and maintaining, aselected or given gear ratio an electro-hydraulic distributing unitcontrolling the hydraulic couplings, which is responsive to ordersreceived from hydro-pneumatic members measuring the engine torque andservo-action electrical and electronic elements;

these electrical and electronic servo-action elements designed forconverting into electrical control signals the resultant of thecomparison between the relative speed of the vehicle measured from theoutput shaft of the change-speed transmission mechanism, and the ordersissued by the driver which are detected by the position of the throttlevalve the hydraulic pump supplying fluid to the various mechanism andrequiring for its operation a fluid under a regulated pressure thedifferential gear connecting the rotational movements of the outputshaft of the transmission mechanism to the shafts driving the propellingwheels of the vehicle;

the device for measuring the relative speed of the vehicle.

A specific design of such automatic change-speed transmissions appearsin the mounting thereof on motor vehicles having a transverse-mountedpower unit wherein the axes of rotation of the crankshaft, of the gearbox shafts and of the drive wheel shafts are substantially parallel andperpendicular to the longitudinal axis of the vehicle. This specificarrangement, advantageous on account of its considerable compactness, isattended on the other hand by difficult problems arising from thenecessity of combining more or less compatible properties such as greatsturdiness, light weight and simplicity in the manufacture andassembling of the complete mechanism.

The solutions usually resorted to in this field do not meet completelythese requirements as a rule and consist mainly of compromises in whichone more desirable properties are sacrificed to the benefit of otherproperties.

In fact, in many known designs it is observed that the manual gear boxis enclosed in a two-section casing having a joint plane parallel to ordisposed along the axes of the input and output shafts of the mechanism.This type of gear casing require an assembling gasket of relativelylarge surface area which must apply to a strictly flat surface obtainedthrough a very accurate machining operation. Furthermore, assembling thetwo casing halves or sections involves the use of additional sturdyassembling members near the bearings in order to absorb the reactions ofthe driving pinion of the differential.

It is the essential object of the present invention to provide animproved design of the casing of the change-speed mechanism wherebyajoint plane having a reduced surface area can be used.

Another object of this invention is to facilitate the access andassembling of certain component elements of the transmission mechanismthrough the use ofinterfitting casing sections of elements.

A complementary object of the present invention consists in providing anarrangement of the cavities for receiving the oil for lubricating theelements of the change-speed mechanism and of the engine with a view toimproving the transmission efficiency.

The power unit according to this invention, disposed transversely to thelongitudinal axis of the motor vehicle and comprising a casing for thetorque converter, a main casing for the change-speed transmissionmechanism and the differential mechanism, which is made of detachableelements, connected to the engine unit along orthogonal assemblingplanes, an epicyclic gear change-speed mechanism comprisingfrictioncoupling members, at least one input shaft and one output shaftdisposed coaxially to each other, a device for measuring the relativespeed of the vehicle which is coupled to the output shaft, ischaracterized in that the torque converter casing and the casingenclosing the friction coupling members of the change-speed mechanism,connected in a manner already known per se along two orthogonalassembling or joint planes, are mutually centered by means of acylindrical fitting surface, and that the casing enclosing said frictioncoupling members comprises at least one detachable casing elementassembled on the one hand to the main casing of the transmissionmechanism which carries the speed measuring device along an assemblingplane perpendicular to the assembling plane of the engine unit, and onthe other hand to the torque converter casing.

Under these conditions it is clear that the orthogonal or perpendicularassembling planes of the proposed arrangement have a minimum surfacearea and are no more the seat of stresses tending to separate the casingelements, comparable to the stresses exerted on the bearings of thetransmission casing. Thus, the largediameter bolts provided in thehitherto known designs for reacting to the bearing buttressing effortsproduced in conventional designs can be dispensed with.

The automatic change-speed transmission mechanism for automotive vehiclehaving a transversemounted power unit thus obtained permits combiningthe desirable properties of sturdiness, light-weight and simplicity ofmanufacture and assembling of the mechanism as a whole, while preservingthe advantageous feature of considerable compactness.

. Other features, objects and advantages of this invention will appearas the following description proceeds with reference to the attacheddrawings. Of course, various changes may be brought to detailsconcerning the construction, design and arrangement of the componentelements of which a preferred form of embodiment is illustrated by wayof example, without however departing from the spirit and scope of theinvention as set forth in the appended claims.

In the drawings FIG. 1 is an elevational view of a longitudinal sectionof the power unit, the section being taken along the line A-A of FIG. 3

FIG. 2 is a view from above of a longitudinal section taken along theline B-B of FIG. 3, and

FIG. 3 is a cross sectional view of the power unit, taken along the lineCC of FIG. 1.

It will be noted that in the figures only those portions of the powerunit and transmission mechanism that are necessary for a properunderstanding of the invention are designated by reference numerals.

Referring first to FIG. 1, the hydro-kinetic torque converter 1 ismounted to the output end of the engine crankshaft 2. The input memberor pump 3 of the converter is rotatably solid with the crankshaft and ofthe gear pump 4, the output member or turbine 5 being rigid with a shaft6 provided with a pinion 7.

A driving member 8 meshes with pinion 7 and another pinion 9 rigid withthe shaft 10 and also with pinion 11. This pinion 11 is in meshingengagement with a pinion 12 rigid with the input shaft 13 of thechange-speed transmission mechanism. This shaft 13 is connected to theoutput shaft 14 of the mechanism through one or a plurality of epicyclictrains 15 responsive to a set of friction coupling members 16. 1

These friction coupling members 16 are controlled by hydraulic signalsdelivered from the electro-hydraulic distributing unit showndiagrammatically at 17. This electro-hydraulic distributing unit 17utilizes electric signals generated in an electronic unit 31 (FIG. 2)mounted on the speed measuring device 18, and also the hydraulic signalsgenerated by a hydro-pneumatic detector (not shown). The electronic unitand the hydropneumatic detector are no part of the present invention andtherefore notdescribed in detail herein. Useful reference may be made inthis respect to the US. Pat. Nos. 3,495,469 of Feb. 17, 1970 and3,505,909 of Apr. 14, 1970.

The relative speed of the vehicle is measured by a tachometricalternator 18 mounted directly to the end of the output shaft 14 of thechange-speed mechanism, without any reduction or bevel gearing.

The input shaft 13 and output shaft 14 of the changespeed transmissionmechanism are supported by plain bearings such as 19, 20 between whichthe driving pinion 21 of the differential is disposed, as shown in FIG.1.

Beyond the bearing 20 is a toothed wheel 22 having the function oflocking the shaft 14 for holding the vehicle in the parking position.Between the wheel 22 and alternator 18 is another pinion 23 adapted totransmit the motion to the speedometer on the instrument panel of thevehicle.

All these mechanisms are mounted in a casing assembly 24, 25, 26 rigidlyconnected to one another and to the engine crankcase or block 27. Thesecasings comprise fluid-tight closing plates such as 28, 29 or covers 34,35.

The casings 24 and 25 are also centered to each other by means of acylindrical fitting 30.

FIG. 1 shows how the stator of the tachometric alternator 18 is rigidwith a cap 26 fitted in the casing 26 enclosing the epicyclic trains ofgears and also the manner in which the rotor of this alternator iscoupled to the free end of the output shaft 14 of the changespeedtransmission mechanism.

The casing 26 enclosing likewise the differential mechanism 32 comprisesa cover 34. The plane 37 along which the cover 34 is assembled to thiscasing 26 may advantageously extend at right angles to the assemblingplane 36 of the engine cylinder crankcase or block (FIG. 3).

Another cover 35 of casing 26 forms in conjunction with an innerpartition 44 cast in said casing the sump in which the enginelubricating oil is kept.

To facilitate the machining of this casing 26 the assembling or jointplanes 38 and 39 of cover 35 and closing plate 29 are alsoperpendicular. Thus, it will be seen that the automatic change-speedmechanism has a particular design adapted to be used in a motor vehiclehaving a transverse-mounted power unit whenever it is desired to combinea'considerable compactness with properties such as sturdiness, minimumweight and simplified manufacture and assembling.

The closing plate 29 of main casing 26 which lies at the lower portionof the power unit and transmission assembly defines a capacity 40constituting the cavity for retaining the oil necessary for lubricatingand operating the change-speed mechanism proper.

This casing 26 comprises an integral partition 41 disposed between themain cavity 40 and the chamber 42 surrounding the friction couplingmembers 16. The

aforesaid partition 41 will thus prevent the splashing (generated by theoil inertia during strong accelerations of the vehicle) of thesefriction members, thus reducing accordingly the slippage of clutch disksor brakes incorporated in the transmission, as this slippage would bedetrimental to the efficiency of operation of the transmission.

FIGS. 1 and 3 illustrate more clearly the arrangement of the variousassembling planes or joint planes of casing 24 (enclosing the torqueconverter 1) and casing 25 (enclosing the friction coupling members 16).The other casings 24, 25 are connected to the engine crankcase 27 bymeans of perpendicular joint planes 36, 36'.

FIG. 2 shows on the other hand the position of the electronic unit 31mounted on the tachometric alternator 18 as well as the differentialmechanism 32 of which the crown wheel 33 is in constant meshingengagement with its driving pinion 21.

FIGS. 1 and 2 show how the casing 25 is connected on the one hand to themain casing 26 along an assembling or joint plane 43 perpendicular tothe joint plane 36 of the engine crankcase, and on the other hand to theconverter casing 24 by means of the aforesaid cylindrical fitting 30.

What is claimed as new is:

l. A power and transmission unit for a motor vehicle adapted fordisposition in a direction transverse to the longitudinal axis of amotor vehicle, comprising:

an engine crankcase;

a change-speed transmission mechanism comprising epicyclic trains ofgears and friction coupling members and at least one input shaft and oneoutput shaft disposed coaxially to each other;

a differential mechanism;

a device for measuring the relative speed of a vehicle, said deviceconnected to the output shaft of said change-speed mechanism;

a hydrokinetic torque converter;

a main casing enclosing a portion of said changespeed mechanism and saiddifferential mechanism;

a second casing enclosing said hydrokinetic torque converter, each ofsaid casings comprising a detachable section connected to the enginecrankcase along ajoint plane;

a third casing enclosing the friction coupling members of the changespeed mechanism, said third casing comprising at least one detachablecasing section connected to said main casing along ajoint plane which isperpendicular to the major axis of the crankcase, and connected to saidsecond casing and the joint plane between the second casing and thecrankcase is perpendicular to the joint plane between the third casingand said crankcase, and said second and third casings are aligned witheach other by means of cylindrical fitting surfaces on each of saidcasings.

2. Enclosures for the power and transmission units of a motor vehicle,comprising:

a. an engine crankcase;

b. a main casing for enclosing a portion of a changespeed transmissionmechanism, and for enclosing a differential mechanism;

c. a second casing for enclosing a hydrokinetic torque converter, eachof said casings comprising a detachable section connected to saidcrankcase along ajoint plane;

d. a third casing for enclosing a further portion of a change-speedmechanism, said third casing comprising at least one detachable casingsection connected to said main casing along a joint plane which isperpendicular to the major axis-of the crankcase, and connected to saidsecond casing; and the joint plant between the second casing and thecrankcase is perpendicular to the joint plane between the third casingand said crankcase; and said second and third casings are aligned witheach other by means of cylindrical fitting surfaces on each of saidcasings.

3. Power and transmission unit according to claim 1, characterized inthat the speed measuring device comprises a tachometric alternatorhaving its stator rigid with the third casing enclosing the epicyclictrains of gears and its rotor coupled to the free end of the outputshaft of said change-speed transmission mechanism.

4. Power and transmission unit according to claim 1, characterized inthat the input shaft of said changespeed transmission mechanism isdriven from said torque converter through a shaft carrying two pinionsmeshing the one with the member driving said torque converter and theother with a pinion rigid with the input shaft of the change-speedtransmission mechanism.

5. Power and transmission unit according to claim 4,

characterized in that said input shaft and output shaft of thechange-speed transmission mechanism are carried by plain bearings.

6. Power and transmission unit according to claim 1, characterized inthat the main casing of said changespeed mechanism comprises a coverforming with an internal partition cast integrally with said casing acavity constituting the engine lubricating oil sump.

7. Power and transmission unit claim 1, characterized in that the maincasing enclosing the differential is provided with a cover of which thejoint plane is perpendicular to the joint plane of the engine crankcasewith the change-speed main casing.

8. Power and transmission unit according to claim 1, characterized inthat the main casing comprises at least one closing member forming withan internal partition of said casing a cavity adapted to receive the oilfor lubricating the change-speed transmission mechanism, said cavitybeing separated by said partition from the space enclosing said frictioncoupling members.

1. A power and transmission unit for a motor vehicle adapted fordisposition in a direction transverse to the longitudinal axis of amotor vehicle, comprising: an engine crankcase; a change-speedtransmission mechanism comprising epicyclic trains of gears and frictioncoupling members and at least one input shaft and one output shaftdisposed coaxially to each other; a differential mechanism; a device formeasuring the relative speed of a vehicle, said device connected to theoutput shaft of said change-speed mechanism; a hydrokinetic torqueconverter; a main casing enclosing a portion of said change-speedmechanism and said differential mechanism; a second casing enclosingsaid hydrokinetic torque converter, each of said casings comprising adetachable section connected to the engine crankcase along a jointplane; a third casing enclosing the friction coupling members of thechange speed mechanism, said third casing comprising at least onedetachable casing section connected to said main casing along a jointplane which is perpendicular to the major axis of the crankcase, andconnected to said second casing and the joint plane between the secondcasing and the crankcase is perpendicular to the joint plane between thethird casing and said crankcase, and said second and third casings arealigned with each other by means of cylindrical fitting surfaces on eachof said casings.
 1. A power and transmission unit for a motor vehicleadapted for disposition in a direction transverse to the longitudinalaxis of a motor vehicle, comprising: an engine crankcase; a change-speedtransmission mechanism comprising epicyclic trains of gears and frictioncoupling members and at least one input shaft and one output shaftdisposed coaxially to each other; a differential mechanism; a device formeasuring the relative speed of a vehicle, said device connected to theoutput shaft of said change-speed mechanism; a hydrokinetic torqueconverter; a main casing enclosing a portion of said change-speedmechanism and said differential mechanism; a second casing enclosingsaid hydrokinetic torque converter, each of said casings comprising adetachable section connected to the engine crankcase along a jointplane; a third casing enclosing the friction coupling members of thechange speed mechanism, said third casing comprising at least onedetachable casing section connected to said main casing along a jointplane which is perpendicular to the major axis of the crankcase, andconnected to said second casing and the joint plane between the secondcasing and the crankcase is perpendicular to the joint plane between thethird casing and said crankcase, and said second and third casings arealigned with each other by means of cylindrical fitting surfaces on eachof said casings.
 2. Enclosures for the power and transmission units of amotor vehicle, comprising: a. an engine crankcase; b. a main casing forenclosing a portion of a change-speed transmission mechanism, and forenclosing a differential mechanism; c. a second casing for enclosing ahydrokinetic torque converter, each of said casings comprising adetachable section connected to said crankcase along a joint plane; d. athird casing for enclosing a further portion of a change-speedmechanism, said third casing comprising at least one detachable casingsection connected to said main casing along a joint plane whIch isperpendicular to the major axis of the crankcase, and connected to saidsecond casing; and the joint plant between the second casing and thecrankcase is perpendicular to the joint plane between the third casingand said crankcase; and said second and third casings are aligned witheach other by means of cylindrical fitting surfaces on each of saidcasings.
 3. Power and transmission unit according to claim 1,characterized in that the speed measuring device comprises a tachometricalternator having its stator rigid with the third casing enclosing theepicyclic trains of gears and its rotor coupled to the free end of theoutput shaft of said change-speed transmission mechanism.
 4. Power andtransmission unit according to claim 1, characterized in that the inputshaft of said change-speed transmission mechanism is driven from saidtorque converter through a shaft carrying two pinions meshing the onewith the member driving said torque converter and the other with apinion rigid with the input shaft of the change-speed transmissionmechanism.
 5. Power and transmission unit according to claim 4,characterized in that said input shaft and output shaft of thechange-speed transmission mechanism are carried by plain bearings. 6.Power and transmission unit according to claim 1, characterized in thatthe main casing of said change-speed mechanism comprises a cover formingwith an internal partition cast integrally with said casing a cavityconstituting the engine lubricating oil sump.
 7. Power and transmissionunit claim 1, characterized in that the main casing enclosing thedifferential is provided with a cover of which the joint plane isperpendicular to the joint plane of the engine crankcase with thechange-speed main casing.